Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: HashTable upper_bound worthless ?

Author: José Carlos

Date: 11:06:03 02/14/01

Go up one level in this thread


On February 14, 2001 at 12:37:52, Larry Griffiths wrote:

>On February 14, 2001 at 10:11:53, Carmelo Calzerano wrote:
>
>>On February 14, 2001 at 09:35:58, Larry Griffiths wrote:
>>
>>>Carmelo,
>>>
>>>I will dink around with the hash table some more and see if I can find a bug
>>>somewhere.
>>>
>>>Is this Fine 70?
>>>
>>>[D]8/k7/3p4/p2P1p2/P2P1P2/8/8/K7 w - -
>>
>>Exactly ;-)
>>
>>Bye,
>>Carmelo
>
>Ok Carmelo,
>
>I did find a bug in my hash code and am getting upper_bound cutoffs now.
>I owe you one since I was about to give up on the hash table for a while.
>I ran the Fine 70 position using a 16meg hash table.  My hash tables are
>28 bytes in size.
>
>My program goes 17 plys in 18 seconds without the hash table,
>and 19 plys in 6 seconds with the hash table.
>
>I noticed that Hardly any of the 16meg hash table was used.  I am only using 1
>slot per hash key, and maybe if I add/look at the next 8 slots I can get some
>more entries in the hash table and go deeper on plys.

  I don't know what you mean with the slots thing (though I figure), but I think
you may have a problem with the hash codes, because you're doing too slow in
this problem, and don't even fill 1 Mb of the hash...

  I may be wrong, but I think your hash codes are not different enough for
similar positions.

  José C.

>I do not know if I will
>be able to get 33 plys (impressive).  I found a bug in my hash table code a few
>days ago that might explain why my program was making bad moves with my old hash
>table code.
>Thanks so much for your help.
>By the way, what is your chess program name?
>
>Larry.



This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.